The present invention relates to electronic equipment housings and, more particularly, to an articulated housing used in a multi-body modular repeater system in an undersea environment.
Repeaters are commonly used in undersea fiber optic systems to amplify optical signals being transmitted over long distances. A repeater body houses the electronic and optical equipment used to amplify the optical signals and is coupled to a fiber optic cable at each end. Repeaters currently used in undersea fiber optic systems typically accommodate four fiber pairs (i.e., four fibers in each direction of transmission), requiring four amplifier pairs to amplify the optical signals in each of the fibers.
Demands for greater transmission capacity in undersea fiber optic systems have created a need to increase the number of fiber pairs per system in the undersea fiber optic cables. Recent design proposals for fiber optic cables use up to eight fiber pairs (i.e., sixteen total fibers), but the existing repeater bodies have insufficient volume to house the additional amplifier pairs needed to amplify the additional fibers. Future cable system designs are likely to require even more fiber pairs and thus more amplifier pairs.
The use of the fiber optic systems in an undersea environment presents some unique challenges when designing a new repeater body to accommodate the increased number of fibers and related equipment. The existing repeater bodies are designed to be readily manufactured in a repeater factory, shipped to a cable factory, integrated with cables, transported and stored on a cable ship, deployed from the cable ship, and possibly recovered from the undersea environment. These existing procedures need to be considered when implementing a new repeater design.
One proposed solution has been to merely increase the size of the repeater bodies. A size increase would require procedural modifications for handling, integrating, and testing the larger repeater bodies and would result in multiple repeater housing inventory at the factory. The increase in mass and volume of the larger repeater bodies would also present problems with transporting, storing and deploying the repeater bodies. An increase in the length of the repeater body, for example, would result in the longer repeater body not properly contacting the surface of existing cable drums used to deploy the cable from a cable ship. Furthermore, the larger repeater body would not accommodate additional expansion (e.g., beyond sixteen fibers) without a costly and time consuming redesign effort.
Accordingly, there is a need for a repeater system capable of accommodating an increased number of fibers while taking into consideration the unique issues involved with manufacturing, transporting, storing, deploying, and recovering fiber optic cable and repeaters in an undersea environment.
In accordance with the present invention, there is provided a multi-body modular repeater system capable of accommodating an increased number of fibers in a fiber optic system. The multi-body modular repeater system comprises at least first and second repeater bodies connected in tandem. Each of the repeater bodies includes at least repeater circuitry. A fiber optic cable coupled to the first repeater body includes at least a first plurality of optical signal paths and a second plurality of optical signal paths. The first plurality of optical signal paths are preferably processed by the repeater circuitry in the first repeater body and the second plurality of optical signal paths preferably pass through the first repeater body. The second plurality of optical signal paths are preferably processed by the repeater circuitry in the second repeater body and the first plurality of optical signal paths preferably pass through the second repeater body.
In one embodiment, the repeater bodies are connected in tandem with a jumper cable. In another embodiment, the repeater bodies are connected in tandem with an articulating joint.
In accordance with another aspect of the present invention, there is provided an articulated equipment housing system comprising first and second housings for housing electronic equipment. An articulating joint preferably connects the first and second housings to allow angular deflection of the housings while substantially preventing circumferential rotation of the housings with respect to one another. The articulating joint includes a passageway for allowing signal paths to pass through between the first and second housings. A first cable coupling at one end of the first housing is used to couple the first housing to a cable, and a second cable coupling at one end of the second housing is used to couple the second housing to a cable.
According to one embodiment of this aspect of the present invention, a connecting member is connected to at least one of the first and second housings using a gimbal connection. One variation of the connecting member in this embodiment has a neck extending between two wider end portions. Another variation of this connecting member has a wider central portion between the end portions.
According to a further embodiment of the articulating joint aspect of the present invention, a connecting member includes a first end portion pivotally connected to the first repeater body such that the connecting member pivots with respect to the first repeater body about a first axis. The connecting member includes a second end portion pivotally connected to the second repeater body such that the connecting member pivots with respect to the second repeater body about a second axis substantially perpendicular to a plane containing the first axis.
According to yet another embodiment of the articulating joint aspect, first and second connecting members are pivotally coupled to respective first and second repeater bodies such that the first and second connecting members pivot about respective first and second axes with respect to the respective repeater bodies. The first and second connecting members are pivotally coupled and pivot with respect to one another about a third axis substantially perpendicular to a plane containing the first and second axes.
In accordance with yet another aspect of the present invention, there is provided a method of processing a plurality of optical signals carried on optical signal paths within a fiber optic cable connected, in tandem, to first and second processing locations. The method comprises processing optical signals carried on a first plurality of optical signal paths at the first processing location. The optical signals on a second plurality of optical signal paths pass through the first processing location. The optical signals carried on the second plurality of optical signal paths are processed at the second processing location. The optical signals on the first plurality of optical signal paths pass through the first processing location.